Partizan lose first league game in 40
Red Star Belgrade went three points clear of second-placed Partizan with a 2-0 home win over Metalac Gornji Milanovac. Third-placed Vojvodina are a further point adrift.
Partizan, who have won a record three league titles in a row and lost their last league fixture in the 2008-09 season, looked flat in an ill-tempered match in Novi Sad which produced four red cards and 14 bookings.
Winger Mario Djurovski fired Vojvodina ahead with a first-half penalty and Georgia striker Giorgi Merebashvili sealed the home team's victory with a solo effort on the hour.
Merebashvili and team mate Nikola Lazetic, as well as Partizan midfielders Nemanja Tomic and Milan Smiljanic, were sent off for dissent in the second half when the match became littered with fouls and scuffles between players.
Red Star striker Andrija Kaludjerovic scored his sixth goal in seven games for the 1991 European Cup winners and Brazilian midfielder Cadu added the second in a one-sided contest.
At the other end of the table, Cukaricki Belgrade earned their first point of the campaign with a 1-1 draw at Jagodina.